1. Field of the Invention
The present invention relates to an electronic device including a rotation unit provided with a display unit, the rotation unit being capable of detecting a rotating angle of the rotation unit by using a detector capable of detecting a direction and an intensity of magnetic field.
2. Description of the Related Art
In a book-type personal computer, an in-vehicle display device, or the like, a rotation unit having a display unit such as a liquid crystal panel is freely rotatably mounted to a device main body unit. In an electronic device of this type, a sensor for detecting a rotation angle of the rotation unit is provided. When a sensor detects that the rotation unit is rotated up to a predetermined angle, a display of the display unit is turned ON or turned OFF, or display content is switched.
Japanese Unexamined Patent Application Publication No. 2002-132385 discloses a note-type personal computer, in which a detection of a rotation angle of a rotation unit is performed by using an angle sensor built in a hinge part. Japanese Unexamined Patent Application Publication No. 10-309996 discloses an in-vehicle display device having a rotation unit. In this display device, an angle of the rotation unit is detected on the basis of an encoder type detection method or a micro switch.
However, when the angle sensor or the encoder is mounted to the hinge part of the rotation unit, a structure of the hinge part becomes complicated. Also, each time the rotation unit is rotated, the mechanical component such as the angle sensor or the encoder contact or slide, and the life of the angle sensor or the encoder is unavoidably shortened. In addition, the micro switch needs to be arranged at the hinge part of the rotation unit, and it is difficult to find an arrangement space.